pc@hillside.co.uk (Peter Collinson) (06/24/91)
Submitted-by: pc@hillside.co.uk (Peter Collinson) USENIX Standards Watchdog Committee Stephen R. Walli <stephe@usenix.org>, Report Editor Report on POSIX.17 - Name Space/Directory Services Mark Hazzard <markh@rsvl.unisys.com> reports on the meeting in Chicago, Illinois: Summary The POSIX.17 group is generating a user to directory services API, for example an API to an X.500 Directory User Agent (DUA). We are referring to a network idea of a directory, not the ``file which contains file entries'' defined in POSIX.1. It is not limited to just the X.500 functionality. We are using XAPIA - X/Open's Directory Services specification (XDS) as a basis for work. XDS is an object oriented interface and requires a companion specification for object management (XOM). XOM is a stand-alone specification with general applicability beyond the API to directory services. It will be used by IEEE 1224.1 (X.400 API) and possibly other POSIX groups, and is being standardized by IEEE 1224. We made significant progress on a third draft of the document in Chicago, with the language independent specification work still to be done. We hope to mock ballot the document sometime after the July working group meeting. POSIX.12 (Protocol Independent Interfaces) and POSIX.17 worked together this week and arrived at a number of scenarios for coordinating the work. POSIX.17 is taking steps to determine if their work overlaps with the proposed work of certain ISO/SC21 (OSI) working groups. Status Commitment within the group remains adequate, but there's more than enough work to go around. Chris Harding, our Technical Editor (from X/Open), brought a second draft of the specification to the meeting. We made significant progress towards producing a third draft with emphasis on format cleanup, model, overview sections and test assertions. The ``homework'' assignments on Language Independent Specification (LIS) weren't completed and additional work on LIS was put on hold until the outcome of the SEC meeting. There seemed to be some confusion as to the applicability of the LIS requirement for POSIX.17 and other Distributed Services APIs. The SEC reaffirmed the LIS requirement. The LIS work was reassigned to the Technical Editor. The big debate on generalizing the Object Management API never materialized. (Refer to the three snitch reports on the New Orleans 1991 meeting.) I strongly suspect this was largely due to the absence of Scott ``Owls in the bushes'' Guthrey at the Chicago meeting. Requirements from POSIX.12 The group met with POSIX.12 (Protocol Independent Interfaces) to get their requirements for the POSIX.17 API. They expressed the desire (necessity?) to: - access existing directory services (e.g. DNS) via the POSIX.17 API - map the existing BSD API (e.g. gethostbyname, getservbyname, etc.) onto the POSIX.17 API. We discussed at length how these and other requirements should best be met, and produced three different scenarios describing relationships between the user application, the directory API(s), the directory service(s) and the transport service (accessed via POSIX.12's Simplified Network Interface). In the first scenario, the transport provider (SNI) would talk directly to all directory services e.g. DNS, X.500, etc. Each directory service resolver would be accessed through its native interface, of which POSIX.17 would be just another API. In scenario two, POSIX.17 would be the only API and would be used to access all directory services. To access a non- X.500 DUA, the underlying implementation might have to translate POSIX.17 calls into the appropriate format and invoke the corresponding resolver. In the final scenario, POSIX.17 would again be the only API, but only one resolver (X.500 DUA) would be used to query a single composite information base (DIB) containing information on all objects (e.g. DNS Resource Records and X.500 Distinguished Names). In each of the scenarios, impact to the POSIX.17 API will be minimal. However, significant impact is anticipated for the underlying implementation and directory information base. We discussed the relative merits of each and decided that at some future time a single API, resolver (agent), directory service and information base just might be the best for POSIX systems. We also recognized that POSIX systems will need to interoperate with non-POSIX systems for the foreseeable future, and that fact won't be lost on implementors. Live long and prosper! or Extending the life of our standard The base document defines both the API and the collection of objects managed through the API, called a ``package.'' We believe that packages will be much more dynamic than the API itself, and could be unbundled from the API to give the API greater stability. We actioned the Distributed Services Steering Committee (DSSC) to recommend a common solution, as this problem is shared by other networking groups. We expect the DSSC to take this issue up in Santa Clara. Mock Ballot We decided to try to mock ballot our document sometime after the July meeting. After reaching agreement on the minimum document content for mock ballot, we assigned actions to get this work done. We wish to solicit input on requirements and feedback on our LIS and Test Assertion work. Is SC21 doing APIs too? With the granting of any IEEE project request (PAR) comes a responsibility to coordinate with other de jure standards bodies, the list of which is included on the PAR itself. In fulfilling this obligation, the group has learned (and dutifully reported to the SEC) that ISO SC21 is considering working on APIs to OSI application level services. This work has a potential to overlap the SC22 supported work being done by IEEE TCOS/POSIX (e.g. POSIX.17, P1224, P1238). In Closing ... The group made good solid progress in Chicago, and our document is beginning to ``flesh out.'' We think we understand what's required for test assertions and language independence, and have done several things to make the base document more readable. If we can maintain ``critical mass'' within the group, we have a good chance of going to mock ballot yet this year. There's a lot of work to do, so if anyone out there can make it to Santa Clara in July ... Volume-Number: Volume 24, Number 17